The present invention relates to a display device, a color filter substrate and a manufacturing method thereof.
Color filter substrate (CF) is an important component of a thin film transistor liquid crystal display (TFT-LCD). A liquid crystal display mainly depends on the color filter substrate to be able to present colorful images. White light from the backlight transmits through the liquid crystal layer and irradiates on the color filter substrate. Then it passes through red, green and blue color filters corresponding to each pixel on the color filter substrate and form red, green and blue lights. They are finally mixed into color images in human eyes. The color filter substrate accounts for significant costs in a TFT-LCD display panel. For a 15 in. panel, the color filter substrate accounts for about 24% in terms of material cost. It's convenient to realize color display with color filter substrates and it is possible to obtain quite high color purity and relatively wide color reproduction range, therefore this manner has become a dominant manner for multi-colorized or full colorized liquid crystal displays.
As shown in FIG. 1, a conventional color filter substrate includes: a substrate 1; a black matrix 2 formed on the substrate 1; a color resin layer 3 formed in exposed pixel regions of the black matrix 2, which includes a red resin layer (R, denoted by right oblique lines in the figure), a green resin layer (G, denoted by mesh lines in the figure) and a blue resin layer (B, denoted by left oblique lines in the figure); a planarization layer 4 formed on the substrate 1 with the color resin layer 3 formed thereon; and spacer (PS) 5 formed on the planarization layer 4. In case of a twisted nematic (TN) liquid crystal panel, a transparent conductive layer (not shown in Figs.) is further disposed in the color filter substrate, which is over the planarization layer 4 and on which is formed the spacer 5.
With the development of TFT-LCD technology, the requirement on transmissivity of the color filter substrate is becoming higher and higher. As shown in FIG. 2, in order to improve transmissivity of the color filter substrate, a solution is proposed to design light holes 6 in the color resin layer 3, wherein light holes 6 may be adjusted in their sizes as required, which occupy about 3%˜4% area of the sub-pixel area.
When the color filter substrate is designed with light holes, in the conventional process, an over coat (OC) is typically applied on the black matrix and the color resin layer to form the planarization layer of the color filter substrate and depressions at light holes are filled with the OC material. However, as shown in FIG. 3, while forming the planarization layer 4, due to insufficient filling of OC material at the light holes 6, collapses 7 and too big steps would occur at light holes 6, causing poor alignment of liquid crystal.